Plug-in devices



FIG. 1 is a front elevational view of a plug-in device showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is an elevational view of the right side thereof;

FIG. 4 is an elevational view of the left side thereof; and,

FIG. 5 is a perspective view thereof.

The broken line portion of the figure drawings is included to show unclaimed subject matter only and forms no part of the claimed design. 

The ornamental design for a plug-in device, as shown and described. 